[vsnet-chat 4359] Re: V1436 Aql

[Chris Lloyd <cl@ast.star.rl.ac.uk>]

Doh,

Well you can't win 'em all. Having looked at the Tycho data there is no
evidence of any variability in the so-called V1436 Aql, although it must
be said the scatter is very large. However, there is certainly no
indication of any eclipses, and the data are inconsistent with the period
from the Hipparcos data. In detail there are specific inconsistencies
between the two set of data. I quote one telling example.

Hipparcos gives

8508.84701   9.6824  0.036    0
8508.86133  10.0884  0.036    0
8508.93588  10.4629  0.028    0
8508.95025  10.6776  0.044    0

with (relatively) small errors and no flags which clearly shows an
"eclipse"

while at the same time Tycho V gives

8508.86120   9.470 0.219
8508.86121   9.395 0.166
8508.93568   9.263 0.206
8508.93575   9.617 0.196
8508.95003   9.662 0.281
8508.95011   9.094 0.148

large errors but no variation.

On the general point, Hipparcos has good light curves of known variables
at least as faint as this one, so I think that there are particular
problems associated with these observations. Certainly the errors are
meaningless. It appears that there were problems in deriving the solution
to the Hipparcos data which were only resolved after the catalogue was
published. If so then the epoch photometry may be worthless.

Cheers

Chris Lloyd

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